During the period of December 1, 1995, to November 30, 1996, an additional 7 siblings who had had a baseline coronary aniogram in the sibling study underwent a two-year follup-up angiogram to determine the rate of progression of coronary atherosclerosis in this high-risk population. The acceptance rate for follow-up catheterization continues to be about 65% for men and 40% for women. In a few individuals, significant progression of coronary disease has been apparent, but in most, the severity of the lesions visually has not changed. We are in the process of digitizing and quantifying the narrowings in each of the coronary artery segments to more precisely measure the rate of progression. We will analyze the relationship between the rate of progression and the adequacy of risk-factor modification.